Method of and apparatus for dry spinning



Nov. 13, 1934. w, WHITEHEAD 1,

METHOD OF AND APPARATUS FOR DRY SPINNING Filed June 1'7, 1929 FILAMENTS PRECIPITATING PRECIPITATING BATH SPINNING JET INVENTOR. William Whitehead ATTORNEYS Patented Nov. 13, 1934 PATENT OFFICE METHOD OF AND APPARATUS FOR DRY SPINNING WVillia-m Whitehead, Cumberland, Md., assignor to. Celanese Corporation of America, a corporation' of Delaware Application June 17, 1929, Serial No. 371,420

9 Claims.

This invention relates to method of and apparatus for the spinning of filaments, yarn, bristles and the like from solutions of derivatives of cellulose and relates more particularly to the dry spinning of the same in an upward direction.

An object of my invention'is to provide means for facilitating the starting of the operation of a dry spinning machine wherein the filaments, threads and the like are drawn upwardly from 10 the jet through which they are extruded. Other objects of my invention will appear from the following detailed description.

The dry spinning of filaments, threads and the like in an upward direction presents many desirable advantages. However in the employment of upward spinning in a dry process involving the evaporation of the volatile solvent from the spinning solution, diificulty has been encountered in starting the operation of the spinning machine.

If an attempt is made to start the operation by merely wiping the face of the jet, the further spinning solution that is subsequently extruded through the orifices of the jet merely accumulates thereon.

I have found that if in starting the spinning, the spinning solution is caused to passthrough a precipitating bath which temporarily surrounds the spinning jet, the filaments formed by precipitation or coagulation in the precipitating bath rises upwardly in the same and the filaments may be then drawn through the evaporative atmosphere to the winding device.

In accordance with my invention, I provide means for starting the operation of a dry spinning machine which means comprises a receptacle ments and the like that are thus formed are then' drawn through the evaporative atmosphere to suitable winding devices, and then the precipitating bath is removed from the jet so as to permit continuous dry spinning.

By my invention any suitable filaments of say below 1 to 25 or more denier, yarns, bristles, of say 25 to 3000 denier or more, or artificial straw of say 25 to 3000 denier or more may be made. For the formation of these materials, jets are employed which may have-a plurality of orifices of circular or other shapes such as slits, of such configuration and of such size as to make the filaments, bristles or straw of desired shape and size.

Any suitable solution of a derivative of cellulose in a volatile solvent may be employed in the spinning. The derivatives of cellulose may be cellulose nitrate or organic esters'of cellulose or cellulose ethers. Examples of organic esters of cellulose'are cellulose acetate, cellulose formate, cellulose propionate and cellulose butyrate while examples of cellulose ethers are ethyl cellulose, 'methyl cellulose and benzyl cellulose. Examples of suitable volatile solvents are acetone, mixtures of acetone and water or ethyl or methyl alcohol or methylene chloride and methyl or ethyl alcohol, etc..

As stated, the filaments or threads are caused to pass upwardly through the heated evaporative atmosphere, which may be hot air or heated inert gases such as nitrogen or carbon dioxide. The filaments or threads need not. necessarily be drawn upwardly in a vertical direction but they may be drawn at any suitable angle upward from the horizontal. I The precipitating bath employed for aiding the starting of the operation of the spirming process may be placed in a cup or other receptacle surrounding the jet and after operation is started, this cup may be removed or the precipitating liquid may be drained therefrom. This precipitating' bath'may be any suitable one such as water, benzene, methyl alcohol, kerosene or other liquid that does not dissolve the derivative of cellulose employed, and for reasons pointed out above is preferably one of low surface tension when fine filaments are to be'formedr In order further to illustrate my invention, reference is had to the accompanying drawing,

wherein Figure 1 shows a spinning jet for upward spinning provided with a device in accordance with my invention andset at an angle of 45, and

Figure 2 shows a similar device set vertically. Referring .to the drawing in both-figures, 1 indicates a spinning jet having the face 2 perforated with a suitable number of orifices of desired size and'shape; The spinning solution is fed to the jet 1 by means of the pipe 3 and the filaments that are formed are indicated generally at 4. The whole device is placed in the spinning case or metier 5, only part of which is shown.

'Incarrying out my invention, a cup 6 having the precipitating bath 7 therein is provided, and this cup 6 is placed around the jet 1 and is secured to the pipe 3 in any suitable manner. If desired a fitting 8 may be employed for so securing the cup 6 that it may be caused to slide up and down the pipe 3 with a fluid tight joint, so that the cup may be placed in any position, and after the operation of spinning has been started, 110

may be lowered so that the face 2 of the jet is out of contact with the precipitating bath. In order to provide means for draining the precipitating bath from the cup 6, a pipe 9 is provided having a cook 10 leading to the outlet pipe 11.

As one example of the mode of operating the device, a spinning solution comprising 1 part by weight of an acetone soluble cellulose acetate dissolved in 3 parts by weight of acetone is introduced through the pipe 3 and forced through the orifices of the face 2 of the jet. The cup 6 is filled with water and the threads of spinning solution issuing from the orifices of the jet are coagulated because of the percipitation of the cellulose acetate. These precipitated threads do not adhere to the face of the jet, but flow upward and away therefrom. These precipitated filaments ,are gathered up and Wound off at a suitable speed say of 90 meters per minute through the evaporative atmosphere in the metier 5 to any suitable winding or winding and twisting device such as a cap spinning machine. The operation being initiated, the water may be; withdrawn from, the cup 6 by opening the cook 10, or if desired the cup 6 may be lowered so that the face 2 of the 1 jet is no longer submerged in the water.

If desired means may be provided for automatically withdrawing the Water from the face 2 of the jet after the spinning operation is initiated.

I have found it desirable in the spinning of fine filaments to employ a precipitating bath that has low surface tension, since if the liquidhas a high surface tension, the filaments 4 are'forced together and when the liquid level is low, are drawn across the jet face at right angles thereto, thus breaking them oif.

If water is employed as a precipitating bath, its surface tension may be materially decreased by dissolving therein suitable salts and particularlysoaps such asthe oleates or stearates of sodium, potassium or triethanol amine. as sodium acetate or sodium sulphate are useful for this purpose. Usually about 2% of these salts or soaps is sufiicient to. produce the required lowering of the surface tension.

Instead of employing water as the precipitating medium, liquid such as benzene, methyl alcohol,

ethyl alcohol or carbon tetrachloride having much lower surface tension may be employed, and if the surface tension is to be further lowered, salts or soaps may be dissolved therein.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of this invention.

Having described my invention what I claim and desire to secure by Letters Patent is:

1..1he method of initiating the spinning of artificial filaments which comprises extruding a solution of a derivative of cellulose in a solvent through orifices into a liquid precipitating bath, drawing the filaments or threads thus formed through an e-vaporative'atmosphere and then removing the precipitating bath from the path of the filaments 01' threads being spun.

2. The method of initiating the spinning of artificial filaments which comprises extruding a solution of cellulose acetate in a volatile solvent Other" salt such through orifices into a liquid precipitating bath, drawing the filaments or threads thus formed through an evaporative atmosphere and then removing the precipitating bath from the path of the filaments or threads being spun.

3. The method of initiating the spinning'of artificial filaments comprising extruding a solution of a derivative of cellulose in a solvent upwardly through orifices into a liquid precipitating bath, drawing the filaments or threads thus formed through an evaporative atmosphere and then removing the precipitating bath from the path of the filaments or threads being spun.

4. The method of initiating the spinning of artificial filaments comprising extruding a solution of cellulose acetate in a volatile solvent upwardly through orifices into a-liquid precipitating bath, drawing the filaments or threads thus formed through an evaporative atmosphere and then removing the precipitating bath from the path of the filaments or threadsbeing spun.

5. The method of spinning fine filaments containing derivatives of cellulose comprising extruding a solution of a derivative of cellulose in a volatile solvent. through fine orifices in a precipitating bathcontaining a liquid of low surface tension, drawing the fine filaments thus formed through an evaporative atmosphere and then removing the precipitating bath' from the path of the filaments being spun.

, 6. The method of spinningfine filaments containing cellulose acetate comprising extruding asolution of cellulose acetate'in a volatile solvent through fine orifices in a precipitating bath containing a liquid of low'surface tension, drawing the finefilaments thus formedthrough an evaporative atmosphere and then removing the precipitating bath from the path of the filaments its face, means for extruding a spinning solution through said orifices, means for winding the filaments or threads that are formed, a receptacle for containing a precipitating bath in the path of the filaments or threads and means for removing said precipitating bath.

9. Apparatus for initiating the spinning of artificial filaments comprising the combination of a casing throughwhich an evaporative gas is adapted to-fiow, a spinning jet having orifices in its face, means for extruding a spinning solution through said orifices, means for winding the filaments or threads that are formed, a receptacle for containing a precipitating bath surrounding the face of said jet and means for removing the precipitating liquid bath from around the face of said jet. I

WILLIAM WHITEHEAD. 

